Tinea pedis

Tinea pedis is most frequently due to Trichophyton rubrum, T. interdigitale (formerly known as T. mentagrophytes var. interdigitale) or Epidermophyton floccosum. Tinea pedis has various patterns and may affect one or both feet.

Chronic hyperkeratotic tinea refers to patchy fine dry scaling on the sole of the foot

Moccasin tinea is hyperkeratotic tinea affecting the skin of the entire sole, heel and sides of the foot

Athlete's foot refers to moist peeling irritable skin between the toes, most often in the cleft between the fourth and fifth toes. It is not always fungal in origin and is often associated with bacterial infection and irritant dermatitis

Clusters of blisters or pustules on the sides of the feet or insteps are confused with pompholyx eczema

Round dry patches on the top of the foot may appear similar to psoriasis

Tinea pedis is more common in adults than in children and frequently recurs after initially successful treatment with topical antifungal agents because of reinfection. Fungal spores can persist for months or years in bathrooms, changing rooms and around swimming pools.

Mild and localised tinea pedis can be managed with education and topical antifungal agents. Tell the patient to hot wash socks and stockings, and to wipe out shoes with formalin or meths solution. They should be advised that the condition is mildly contagious, and to wear sandals in changing rooms and not to share towels and footwear. It is likely to recur, so suggest they dry carefully and apply an antifungal powder after bathing long term.

There are numerous topical antifungal agents, of which terbinafine cream (Lamisil™) is probably the most effective. Fully funded options in New Zealand (April 2005) are:

Resistant and extensive culture-confirmed cases of tinea pedis will require oral therapy for one to four weeks, usually with terbinafine or itraconazole (the latter requires specialist approval for PHARMAC subsidy).

Confirmed tinea unguium may require oral antifungal agents for 3 months or longer if the infection is clinically significant and there are no contraindications to treatment. Cure rates depend on the severity of infection, the infecting organism, comorbidities and the age of the patient.